Amazon Linux 2 : cyrus-sasl (ALAS-2026-4029)

high Nessus Plugin ID 371754

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of cyrus-sasl installed on the remote host is prior to 2.1.26-24. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-4029 advisory.

A heap-based buffer overflow flaw was found in Cyrus SASL. The add_to_challenge() function in the DIGEST- MD5 plugin computes the size of the buffer needed for a challenge/response field before DIGEST-MD5 quoting is applied, but does not recompute that size when quoting (escaping special characters) makes the value longer. The under-sized buffer is then passed to strcat(), causing a heap-based out-of-bounds write whose size depends on attacker-controlled input. A malicious or on-path DIGEST-MD5 (or HTTP Digest) server can trigger this flaw in a connecting client by supplying a crafted challenge field, such as realm or nonce, most likely resulting in a crash of the client application. (CVE-2026-107161)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update cyrus-sasl' or or 'yum update --advisory ALAS2-2026-4029' to update your system.

Plugin Details

Severity: High

ID: 371754

File Name: al2_ALAS-2026-4029.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 10/24/2026

Updated: 10/24/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.51

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 5.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-107161

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:cyrus-sasl-debuginfo, p-cpe:/a:amazon:linux:cyrus-sasl-devel, p-cpe:/a:amazon:linux:cyrus-sasl-gs2, p-cpe:/a:amazon:linux:cyrus-sasl-gssapi, p-cpe:/a:amazon:linux:cyrus-sasl-ldap, p-cpe:/a:amazon:linux:cyrus-sasl-lib, p-cpe:/a:amazon:linux:cyrus-sasl-md5, p-cpe:/a:amazon:linux:cyrus-sasl-ntlm, p-cpe:/a:amazon:linux:cyrus-sasl-plain, p-cpe:/a:amazon:linux:cyrus-sasl-scram, p-cpe:/a:amazon:linux:cyrus-sasl-sql, p-cpe:/a:amazon:linux:cyrus-sasl

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 10/24/2026

Vulnerability Publication Date: 10/7/2026

Reference Information

CVE: CVE-2026-107161

Detections

Analytics